Nicaragua's Sandinistas have consolidated their power so thoroughly over the past five years that their victory in November elections is almost inevitable. But opposition leaders may take part in the election anyway because it will ensure some measure of pluralism in Nicaragua, a key opposition leader says.
This political figure, who is highly respected here, says an election - even if it is not completely free - could help steer Nicaragua toward Mexico's style of democracy and away from the Cuban-style political system, which does not allow opposition parties.
''This revolution is a boat that sailed from Havana, but could end up landing in Acapulco,'' says the senior Nicaraguan opposition leader, who asks that he not be named.
The Sandinistas, he believes, are sponsoring an election Nov. 4 in order to help reduce US military and economic pressure on Nicaragua and to stimulate the nation's private sector to help get the economy moving. This is a view shared by a number of other knowledgeable observers of Nicaragua.
The sort of political deal offered by the Sandinistas would ensure that theSandinista National Liberation Front (FSLN) continues to run the the government in the same way the ruling party in Mexico does, this politician says.
But opposition parties would be allowed to function, as in Mexico, and a certain amount of political freedom would be allowed, he says. The private sector and opposition would be given a limited role in the power system.
This prominent figure thinks that the success of the Sandinista plan depends on how vigorously the political opposition is willing to take part in the election. If only fragments of the opposition - such as Clemente Guido's wing of the Conservative Party - participate in the vote, the Sandinistas will decide their olive branch has been spurned and will begin to harden their rule along more radical lines, this politician says. They would radicalize because they know the international community would not extend aid to a nation whose election was considered a farce. Some opposition leaders think Mr. Guido's wing of the Conservative Party is linked too closely with the Sandinistas.
The prominent observer says that the one man with sufficient moral authority to rally the opposition parties for a vigorous campaign would be Conservative Party leader and former junta member Arturo Cruz Porras, Nicaragua's former ambassador to the US. The observer hopes that Mr. Cruz, who now lives in Washington, D.C., will return to Nicaragua to run for office.
The opposition parties must now decide whether they can live with the election plan outlined by the Sandinistas, the opposition leader says. Many opposition leaders would like to come to terms with the Sandinistas but are afraid of being labeled as Sandinista collaborators if they do so, he says. The opposition is suspicious of the Sandinistas' intentions but may prefer the electoral option to the grim alternative of possible US intervention in Nicaragua. But for the opposition leaders to make a deal and accept the plan, this figure says, ''They must first lay aside, once and for all, false hopes that Reagan and the US Marines will come galloping in on white horses to save them from the Sandinistas.''
Like Mr. Cruz, this politician thinks the US Congress and American public opinion would prevent the US from intervening in Nicaragua. The opposition must realize this, he says.
In offering an olive branch to its opponents, he says, the FSLN has also had to realize that its foreign patrons, Cuba and the Soviet Union, will not intervene to save the Sandinistas from any potential US intervention. The Sandinistas also know, he says, that the Soviets will not pour into Nicaragua the massive funds they have given to Cuba, he says.
Some opposition figures would welcome a US intervention in Nicaragua, but many of the democratic opposition leaders do not look on such a prospect as a viable way of gaining power.
''An intervention would be a disaster,'' says Augustin Jarquin, president of the Social Christian Party. ''The Sandinistas and their supporters are heavily armed and prepared to fight on for years in the mountains. Whoever would win the war would lose it. The victors would receive a destroyed country, a country destroyed politically, morally, and economically.''
If the election goes smoothly and many parties participate in the vote, Nicaragua's post-election leaders are likely to be the Ortega brothers - junta coordinator Daniel Ortega Saavedra and Defense Minister Humberto Ortega Saavedra , this source says. The Ortegas are the Sandinistas most closely identified with election plans.
But other key Sandinistas are hoping the elections will fail, he says. One of these is Interior Minister Tomas Borge Martinez, who is more radical than the Ortegas and stands to lose some of his influence if the election goes well, this source says.
In public, Humberto Ortega has come across as more radical and Daniel as more moderate. The opposition leader says there is some truth to this public perception, but he suggests the Ortegas may be projecting differing images as part of a Sandinista attempt to maintain a broad base of support. He strongly feels, however, that once in power, the Ortega brothers would mold Nicaragua's political system along more moderate lines.
Power counts more than ideology, the opposition leader says. He thinks the trend toward liberalization is likely to continue in Nicaragua because the Sandinistas fear the US may take an even harder line against Nicaragua if President Reagan is reelected. Desire to get private sector support to help end the country's severe economic problems is also a factor, he says.
A diplomatic source describes the Sandinista election law as ''basically positive'' but states that it will be difficult to have a free election in a society where the government controls the Army, most of the news media, huge civic organizations, and nearly half of the economy.
Two points not yet clear about the Sandinista election plan are whether the FSLN will let all exile leaders return to Nicaragua to run for office, and what degree of access the opposition will have to television. (The opposition already can buy time on government radio.)
The Sandinistas have said they will allow Arturo Cruz to return home to run for office and might allow Alfonso Robelo to return. It is considered unlikely that revolutionary war hero Eden Pastora Gomez will be permitted even to enter the country. Pastora leads one of the armed groups fighting the Sandinista Army.